Answer:
All circles are similar to each other.
Step-by-step explanation:
Circles are congruent if they have the same radius, regardless of where their centers are located.
Then all circles can't be congruent, because not all of them have the same radius.
Circles are concentric if they have the same center. And not all circles have the same center.
And circles can't be parallels. Parallelism is a relationship that is established between lines or planes.
Then, the correct option is all circles are similar to each other. They all have the same shape although they can be of different sizes, have different centers, and different radius.
